A future wireless system is expected to provide local-area coverage to selected areas, such as offices and homes, where high bit-rates are provided in small cells through inexpensive network infrastructure. Local-area coverage supplements cellular networks, moving traffic away from the expensive cellular network infrastructure to inexpensive local area networks that may use inexpensive internet connections, such as wireless routers, as backbone.
For example, local-area cells may replace wired Ethernet connections between office personal computers (PCs), similar to a wireless local area network (WLAN) with a large number of low-power indoor access points (APs). Each AP covers a relatively small area and serves a small number of users, allowing a high bit-rate per user. Local-area cells may preserve key features of a cellular network, such as reliability, authentication, and excellent mobility.
Conventional network planning to prevent interference between areas served by nearby access points is impractical for a large number of local-area cells. Instead, local-area cells should self-organize use of shared radio resources with minimal operator intervention. However, in a crowded radio environment it becomes increasingly difficult to allocate a sufficient number of resources in a manner that does not conflict with resource allocations by neighboring nodes.
A situation may arise, where a node becomes unable to allocate a sufficient number of resources, while one or more neighboring nodes hold a disproportionally large number of resources occupied.
The difficulty of allocating a new resource increases with the number of neighboring nodes, the number of resources they hold allocated, the geographical layout of a neighborhood of nodes and other factors.
If resource allocation in neighboring nodes is not limited to a fair share of resources, the outcome may be highly unfair. Some mobile devices may gain a strong advantage or suffer a disadvantage compared to others, depending on their path loss between a mobile device and an access point. The successful device with a good quality link may dominate use of the resource, while other devices suffering high path loss or long links may have little or no access to the resource.